In cathode ray tube display devices used to display alpha-numeric and graphic images in a data processing system, such as a small personal computer or computer-controlled TV game, it is often desirable to control the color of the border area surrounding the video or image area in order to make the total display more aesthetically pleasing or easier to view. The color of this border should be controlled independently of the color and data displayed in the video area of the CRT screen.
Controlling the color of the border around the video area of the display screen is different from controlling the color of the edge of an individual character (e.g. U.S. Pat. No. 3,984,828) or the color of the background of a displayed word (e.g. U.S. Pat. No. 3,911,418).